Pneumatically operated die-casting machine



March 10, 1942. L. A. CATLIN ETAL' PNEUMATICALLY OPERATED DIE-CASTING MACHINE Filed June 22, 1940 2 Sheets-Sheet 1 March 10,-1942. A. CATLlN ETAL I 2,275,731

PNEUMATICALLY OPERATED DIE-CASTING MACHINE Filed June-.22, 1940 2 Sheets-Sheet 2 Patented Mar. 10, 1942 I 2,275,731 j I PNEUMATICALLY OPERATED DIE-CASTING MACHINE Leonard Arthur Catlin and Wilfred Henry Cockerill, West Bromwich, England, assignors to E. M. B. Company Limited, West Bromwich,

England Application June 22, 1940, Serial No. 341,978

In Great Britain September 1, 1939 Claims.

Thi invention relates to pneumatically operated die-casting machines, and has for its object to provide improved means for controlling the movements of the dies of such machines.

The invention comprises the combination with a pneumatically operable and relatively slidable piston and cylinder for actuating the movable die head of the machine, and means operable by the attendant for controlling flow of air to and from the said cylinder, of a hydraulic locking device for interrupting the movements of the said die head at desired positions, and controlling means therefor.

In the accompanying sheets of explanatory drawings Figure 1 is a part sectional front elevation, Figure 2 an end elevation, and Figure 3 a fragmentary plan, of a hydraulic locking device constructed in accordance with the invention and applied to a pneumatically operable and relatively movable piston and cylinder for actuating the movable die-carrying plate of a die-casting machine. 7

Figures 4 to 6 are respectively a front elevation, a part sectional plan, and a part sectional side elevation, of the valve mechanism and associated parts employed for controlling the flow of compressed air to and from the cylinder, these figures being drawn to a larger scale than Figures 1 to 3.

As shown in the drawings we employ, for actuating the movable head a which carries a die part or parts of a die-casting machine, a piston b which is slidable in a cylinder 0 under the action of compressed air. rod 01 which at one end passes through a gland e in the corresponding end of the cylinder 0 and is connected by a cross head f and toggle linkage g to the die head a. In Figure 3 the head a is shown in full lines in one extreme position, and in broken lines in the other extreme position. Communicating with opposite ends of the cylinder 0 are a pair of passages it through whichcompressed air can flow between the cylinder and a pair of valve chests i on the underside of the cylinder. Each of these valve chests'contains a spring-loaded inlet valve 51' and a spring-loaded outlet valve is, the valves in the one chest serving to control the fiow of compressed air to and from one of the passages h, and the valves in the other chest serving to control the flow of compressed air to and from the other of the said passages. The valve chests i are situated at a sufficient distance apart to accommodate between them cams m for actuating the valves 7', it, these cams being The piston b is secured on a mounted on a transverse shaft 71 which is rotatably supported by bearings o onthe cylinder 0. Mountedon the front end of the cam shaft n is a hand lever p whereby the shaft can be rocked to actuate the valves 1', k, the stems of these valves being provided with abutment pieces q, r, which project through the adjacent sides of the chests i into the path of the cams m.

In applying the invention as shown to the;

' at both sides of its piston. 20

At each end of its upper side the cylinder u is provided with an opening '0 for establishing communication between this cylinder and an oil or other liquid container w formed or secured on the upper side of the cylinder. The openings 12 are controlled by poppet valves m on the lower ends of vertical stems y which are slidable in fixed guides a situated in the container w. The

valves :1: are loaded by springs 2 which are arranged between heads 3 on the stems and shoulders 4 on the'guides z, and which serve to hold the valves in their closed positionsfor interrupting' communication between the cylinder u and the container w. e,

For opening the valves 0: against the action of the springs 2, we employ a pair of rockers 5 which are mounted, with one pair of ends adjacent to each other, on parallel shafts 6 in the upper part of the container w, and" which are operable by the action on their adjacent ends of a cam or cams 1 situated in the container-at a position between the rockers, the other ends of the rockers being adapted to act on the heads -3 on the valve stems 1. p

The cam or cams 1 is or are mounted on a rotatable shaft 8 which extends through the container w, and'which at one end carries an arm 9, the latter being connected by a link ID to another arm secured to the cam shaft n.

The hand lever 10 for rocking the cam shaft 12 is formed or provided at its lower end with a pair of abutments l2, l3, arranged in different planes, and at a position adjacent to this end is pivotally connected to a slotted extension of the cam shaft by a transverse pin it so that the lever is capable of pivotal movement in a plane containing the axis of the cam shaft. The lever abutments l2, l3 are adapted to co-act respectively with another pair of abutments l5, l6 for actuating the lever p in the manner hereinafter described. These latter abutments l5, l6 are adjustably mounted in spaced relationship and in different vertical planes on rods 11 which are connected at one end to the head a and are slidably supported adjacent to the other end by a bracket l8 depending from the cylinder 0. Normally the lever abutments l2, l3 ar situated in the paths of the corresponding abutment l5, IE, but they can be moved out of these paths by appropriate movement of the hand lever p about its pivot pin M in a forward direction.

In the initial position of the parts above described the head a and hand lever 13 occupy the positions shown in full lines in Figure l, and the valves 7', 7c, :0, are closed. To impart a forward or die-closing movement to the head, that is movement towards the left in Figure 1, the hand lever p is moved from the idle position shown in full lines in Figure 1 to the position 10 shown in broken lines. During this movement of the hand lever p it passes another positionp also shown in broken lines. The movement of the hand lever between its idle position and the position p causes one of the cams m to open the appropriate valves 7', k, for admitting compressed air to the cylinder at the right hand side of the piston b, and releasing the air from this cylinder at the other side of its piston. The piston I), however, cannot be, moved by the action of the compressed air until the valves z of the liquid cylinder have been opened, this being effected by the movement of the hand lever 12 from position p to position 23 When the hand lever p reaches the latter position the piston b commences to move the head or towards the left, and this movement continues until the abutment l comes into contact with thelever abutment l2 and, by acting on the latter, returns the hand lever to the position p for re-closing the valves 0: of the liquid cylinder u. The closing of these valves prevents the flow of liquid between the cylinder u and the container 112, and thereby prevents further movement of the piston t. Consequently, the movement of the air piston b and the head a is interrupted. For enabling the piston b and head a to continue their movement towards the left, the handlever pis pulled forwards against the action of a spring-loaded plunger l9, and then returned to the position 19 the forward movement of the lever causing it to move about the axis of the pivot pin l4 into a position in which the lever abutments l2, l3 are out of the paths of the movable abutments l5, 16 as shown in broken lines in Figure 2. The head a is now moved by the piston h to its closed position as indicated by broken lines in Figure 3.

When it is desired to return the head a to its initial position, the hand lever is moved past the central position to the position 13 shown in broken lines in Figure 1, and during this movement also passes another position 10 The movement of the hand lever between the central position and the position p causes one of the cams to open the appropriate valves 7, k, 'for admitting compressed air to the cylinder 0 at the left hand side of the piston b, and releasing the air from I this cylinder at the other side of its piston. The piston I), however, cannot bemoved by the action of the compressedair until the valves :0 of the liquid cylinder have been opened, this being effected by the movement of the hand lever p from the position p to the position 11 During the return movement of the head a the abutment l6 co-acts with the lever abutment [3 to return the lever p to the position p for interrupting the movement of the head a, the lever being subsequently pulled forwards as above described, and returned to position p for enabling the return movement of the head to be continued under the action of the compressed air on the piston b.

By suitably adjusting the positions of the abutments [5, IS on the rods I! the movements of the head a can be interrupted at any desired positions, and by providing adidtional abutments on the rods each movement of the head can be interrupted at more than one predetermined position if desired.

From the foregoing it will be seen that the liquid cylinder, piston and associated parts form asimple and convenient hydraulic locking device which serves automatically to interrupt the movements of the head a which carries a die part or parts in a reliable manner and exactly at predetermined positions, this arresting of the head being required to enable cores to be inserted and withdrawn from between the fixed and movable die parts of the casting machine when the die parts are in appropriate relative positions. It will also be seen that the hand lever p can be operated by the attendant for causing the locking device to interrupt the movement of and lock the head a in any desired position.

When the apparatus above described is used in a. die casting machine in which molten aluminium or other metal is injected between the die parts under the action of compressed air, it is desirable not only to prevent the molten metal from being injected excepting when the die parts are closed, but also to prevent the die parts from being opened while the molten metal is under air pressure. To satisfy these conditions we employ a rotatable shaft 20 for actuating valve mechanism (not shown) adapted to control the supply of compressed air to metal injecting means (also not shown). This shaft is supported in fixed bearings 2| at the end of the air cylinder 0 adjacent to the die head a, and is provided at its front end with an operating handle 22, the other end of the shaft being connected in any convenient manner to the valve mechanism above mentioned. Also the shaft 20 is formed at different positions with a pair of flattened parts 23, 24 which are situated respectively in keyhole or like slots 25, 25 formed in members 21, 28. The member 21 is formed or provided on one end of a rod 29 which at its other end is pivoted to the arm H on the cam shaft 11, and the member 28 is formed or provided on one end of a rod 30 which at its other end is slidably supported by a fixed part 3l.- Both of the slots 25, 26 are formed as shown with narrow portions which (when occupied'by the corresponding flattenedportions 23, 24 of the shaft 20) serve to prevent rotational movement of the shaft, and with enlarged portions which communicate with one end of the narrow portions, the enlarged portions of the slots being such that (when occupied by the flattened portions of the shaft) they permit rotational movement of the shaft.

When the apparatus is in its initial or inoperative position as shown the flattened portions 23, 24 of the shaft 20 occupy the narrow portions of the slots 25, 26 and rotational movement of the shaft 20 for actuating the compressed air valve mechanism of the metal injecting means is prevented. If now the hand lever p is moved to the position 11 the rod 29 is moved into a position in which the flattened portion 23 of the shaft 20 occupies the enlarged portion of the slot 25 in the member 27, but rotational movement of the shaft is prevented by the engagement of its other flattened portion 24 with the narrow portion of the slot 26 in the member 28. When, however, the die plate a approaches its closed position a projection 32 on the cross head 1 comes into contact with an adjustable abutment 33 on the rod and moves the latter against the action of a spring 34 into a position in which the flattened portion 24 of the shaft occupies the enlarged portion of the slot 26 in the member 28. The shaft 20 can now receive rotational movement for actuating the valve mechanism of the metal injecting means. This rotational movement of the shaft 20 causes its flattened portion 23 to assume such a position in the member 21 that the lever 11) cannot be operated for effecting opening movement of the die head a until the shaft 20 has been returned to its initial position.

The invention is not limited to the example above described as subordinate details may be varied to suit requirements.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

1. Controlling means for a die-casting machine, comprising the combination with a pneumatically operable and relatively slidable piston and cylinder for actuating the movable die head of the machine, and means operable by the attendant for controlling flow of air to and from the said cylinder, of a hydraulic locking device for interrupting the movement of and locking the die head in any desired position under the control of the attendant, and means responsive to the movement of the die head whereby the said device is brought into action automatically for locking the die head in at least one predetermined position.

2. Controlling means for a die-casting ma chine, comprising the combination with a pneumatically operable and relatively slidable piston and cylinder for actuating the movable die head of the machine, and valves for controlling the flow of air to and from the ends of the cylinder, of a second piston and cylinder, the two pistons being interconnected, valves for controlling the flow of liquid to and from the ends of the second cylinder, a lever operable by the attendant for controlling both sets of valves, a pair of abutments on the valve-controlling lever, and additional abutments movable with the die head and adapted by co-acting with the lever abutments, after the lever has been actuated to open the liquid valves, to effect the closing of the liquid valves, the lever being movable in one plane for controlling the air and liquid valves, and in another plane at right angles to the first plane for moving the lever abutments out of the path of the other abutments.

3. Controlling means for a die-casting machine, comprising the oombination with a pneumatically operable and relatively slidable piston and cylinder for actuating the movable die head of the machine, and means operable by the attendant for controlling flow of air to and from ling communication between the liquid container 7 and the ends of the second cylinder, rockers for actuating the valves, a lever operable by the attendant, at least one cam for actuating the rockers, linkage connecting the cam to the lever,

and means movable with the die head for actuating the said lever.

4. Controlling means for a die-casting machine, comprising the combination with a pneumatically operable and relatively slidable piston and cylinder for actuating the movable die head of the machine, and valves for controlling the flow of air to and from the ends of the cylinder, of a second piston and cylinder, the two pistons being interconnected, valves for controlling the flow of liquid to and from the ends of the second cylinder, a lever operable by the attendant for controlling both sets of valves, a rotatable shaft on which the controlling lever is mounted, cams on the shaft for actuating the air valves, linkage connected to the shaft for actuating the liquid valves, and means movable with the die head for actuating the said lever.

5. Controlling means for a, die-casting machine, comprising the combination with a pneumatically operable and relatively slidablepiston and cylinder for actuating the movable die head of the machine, and valves for controlling the flow of air to and from the ends of the cylinder, of a second piston and cylinder, the two pistons being interconnected, a liquid container situated above the second cylinder, spring-loaded poppet valves for controlling communication between the liquid container and the ends of the second cylinder, rockers for actuating the liquid valves, a lever for controlling both sets of valves, at least one cam for actuating the rockers, linkage connecting the cam to the controlling lever, a rotatable shaft on which the controlling lever is mounted, cams on the shaft for actuating the air valves, and means movable with the die head for actuating the said lever.

LEONARD ARTHUR CATLIN.

WILFRED HENRY COCKERILL. 

